Drawing press

ABSTRACT

A drawing press adapted to feed a web of sheet material between a pair of rolls including a first relatively rigid roll extending generally transversely of the path of said web. A second relatively elastic roll urges the web against the first roll and comprises an elongated shaft of elastic material and a plurality of separate, generally cylindrical, disclike weight elements mounted on said shaft in side-by-side relation, each weight element acting by its own deadweight to press said web against said first roll.

United States Patent 1151 3,674,194 Moesser July 4, 1972 [54] DRAWING PRESS [56] References Cited [72] Inventor: Wilhelm Moesser, Darmstadt, Germany UNITED STATES PATENTS [73] Assignees: Otto C. Strecker K.C., Darmstadt- 924,900 6/1907 Gay ..29/125 Eberstadt; Maschinenfabfik zum BM 2,168,572 8/1939 Land1s ..,.226 185 derhaus GJHJLH. Reutlinger wuerttenh Bartels0n. X berg Germany 3,073,590 1/1963 Romeo ..226/l87 x [22] Filed: Nov. 13, 1969 Primary Examiner-Richard A. Schacher pp No 876 449 Attorney-Mason, Kolehmainen, Rathbum & Wyss 57 ABSTRACT [30] Foreign Application Priority Data A drawing press adapted to feed a web of sheet material Nov. 27, 1968 Germany ..P 18 11 203.3 between a p of rolls including a first relatively rigid tending generally transversely of the path of said web. A 52 us. (:1 ..226/187 226/190 Second relatively elastic urges the Web against the first r011 51 Int. Cl ..B6 5h 17/20 and comprises ebngated Shaft elastic material and a P [58] Fieldofsearch ..226/l85 181 186 187 190 Separate, generally cylindma], disclike weigh ments mounted on said shaft in side-by-side relation, each weight element acting by its own deadweight to press said web against said first roll.

10 Claims, 7 Drawing Figures P'A TENTEDJUL 4 1912 3, 674, 194

SHEET 10F Fig.2 PRIOR ART INVENTORI WILHELM MOESSER,

m'smsmunmz 3.674.194

SHEET 20F 3 INVENTORZ PATENTEML] 1972 3,674,192;

sum 30F 3 INVENTOR: WILHELM MOESSE R DRAWING PRESS The present invention relates to a drawing press and one that is particularly suited for drawing a web of sheet material, such as paper, from one or more supply rolls in order to feed the web toward another station for further processing as, for example, a station wherein the web is cut into separate sheets by means of a crosscutter.

The drawing press comprises a pair of rolls which are in contact against opposite surfaces of the web of sheet material and one roll of which (for example, the lower roll) is rotatively driven in order to feed the web, or plurality of webs, situated one above the other forwardly through the rolls.

A prior art drawing press is shown in longitudinal sectional view and cross-sectional view, respectively, in FIGS. 1 and 2 of the drawings herein. In the prior art device of FIGS. 1 and 2 the lower roll 1 comprises a hollow, cylindrical roll 2 with roll ends 3 mounted at opposite ends on a driving trunnion 4 and a bearing trunnion 5, respectively, which trunnions in turn are supported for rotation in bearings 6. The lower roll is drivingly rotated by gear wheels 7 and 8, which are driven by a power source (not shown), such as a gear motor. An upper roll 10 comprises a hollow cylindrical roll 11 having a rubber covering 12 over the outer surface thereof. The roll 11 is supported by a pair of roll ends 13 which in turn are carried by bearing trunnions 14 mounted for rotation in bearings 15. The bearings 15 are mounted on pivotable arms 16 which may be pivotally moved and adjusted toward and away from the lower roll by air cylinders 17. The air pressure in the cylinders may be regulated to adjust the force or pressure with which the upper roll 10 is moved towards the lower roll 1 or, in the alternative, is lifted away to reduce the contact pressure on the lower roll.

A web of sheet material 18, such as paper, in a single layer or in several different layers placed one on top of the other, is gripped and drawn forwards by the rolls 1 and 10 to pass over a feed table 20 and towards a crosscutter or other device (not shown) for further processing.

Because the upper and lower rolls 10 and 1 are supported by the bearings 6 and 15, respectively, at opposite ends of the rolls and because these bearings are spaced outwardly by a distance a from opposite edges of the web 18 passing between the rolls (FIG. 1), the compression force between the rolls and web introduces a bending moment which tends to deflect the lower roll 1 in a downward direction adjacent the middle portion, and this bending moment is in addition to the downward moment caused by the deadweight of the roll itself. The compression forces between the rolls and web tend to urge the middle portion of the upper roll 10 in an upward direction opposite to the direction of the bending moment caused by the deadweight of the upper roll. This results in a nonuniform contact pressure on the web along the length of the rolls and an intensified application of compression force occurs along the opposite edge portions of the web 18, whereas in the middle of the web the compression force is reduced. The application of compression on the web by the rolls 1 and 10 of the prior art device illustrated in FIGS. 1 and 2, is not uniform over the length of the contact line of the rolls on the web, which line extends transversely across the moving web of material.

One means of attempting to obtain a more uniform pressure distribution on the web along the length of the rolls is to provide an upper roll, as mentioned hereinbefore, with an elastic cover made of rubber or other elastic material. In some applications, wherein webs of relatively wide working widths are involved the upper roll is made with a convex or barrel-shaped outer surface having an increased diameter in the middle portion of the roll. When a barrel-shaped roll is used, relative sliding action occurs between the roll and different portions of the web, because of the varying diameter of the roll, and this condition often causes undesirable marking or creasing of the web material. If several webs, lying one above the other, are fed simultaneously between the rolls, one of which is slightly barrel-shaped, feeding errors or relative sliding action occurs between the several layers of web material, and this is caused by the fact that the material in the webs which is furthest removed from the center of the barrel-shaped roll is fed at a slower rate than the material at the center, and each individual web layer is displaced relative tothe others, and this tends to produce wrinkles, ripples, or undulations in the material leaving the rolls.

It is an object of the present invention to obviate the aforesaid disadvantages of the prior art drawing press and to provide a new and improved drawing press wherein the application pressure exerted by the rolls on the web material is substantially uniform across the entire length of contact between the rolls and web.

Another object of the present invention is to provide a drawing press which provides for substantially uniform roll pressure across the width of the web even in cases where a web of narrow width, substantially less than the length of the rolls, is being handled.

Anotherobject of the present invention is to provide a new and improved drawing press which avoids the aforesaid feed ing errors and is especially well suited for a multiple web operation.

Briefly, in accordance with the features of the present invention, one of the rolls in a pair of feed rolls (for example a lower roll) is constructed to be relatively rigid, whereas the upper roll is constructed to be relatively elastic in relation to the lower roll. The upper rOll is not constructed in a unitary, continuous, elongated, tubular body but instead comprises a plurality of separate, disclike, individual weight elements which are mounted on a common elastic shaft and are pressed against the lower roll by their own deadweight.

In accordance with the other features of the invention both the upper roll and the lower roll are provided with an elastic cover, and the external diameter of both rolls is substantially equal and constant across the length of the rolls. In addition, the thickness and elasticity of the elastic cover material is substantially the same on both rolls.

For a better understanding of the present invention, reference should be had to the following detailed description taken in conjunction with the drawings, in which:

FIG. 1 is a transverse cross-sectional view of a drawing press in accordance with the prior art;

FIG. 2 is a longitudinal cross-sectional view of the drawing press of FIG. 1;

FIG. 3 is an elevational view of an upper roll of a drawing press constructed in accordance with the present invention;

FIG. 4 is a diametrical cross-sectional view through a single, disclike weight element used in the roll shown in FIG. 3;

FIG. 5 is an enlarged, longitudinal, cross-sectional view showing portions of upper and lower rolls in contact with a multiple layer web material in accordance with the present invention;

FIG. 6 is a transverse, cross-sectional view similar to FIG. 1 showing a new and improved drawing press constructed in accordance with the features of the present invention and utilizing an upper roll constructed as shown in FIGS. 3 and 4; and

FIG. 7 is a cross-sectional view of the drawing press of the present invention taken on a plane at right angles to the plane of FIG. 6.

Referring now, more particularly, to the drawings, the drawing press of the present invention is shown in FIGS. 3 through 6 and is constructed, except for the upper roll 21 thereof, substantially like the prior art drawing press shown in FIGS. 1 and 2 and previously described herein. Instead of the upper roll 10 of the prior art device, the drawing press shown in FIG. 6, according to the present invention, includes a modified upper roll 21 (FIG. 3). The roll 2] includes a relatively elastic shaft 22 with a plurality of separate, individual, disclike weight elements 23 mounted thereon. A pair of adjustment rings 24 are provided outboard of the outer elements in the roll for preventing longitudinal displacement of the elements on the shaft. The air cylinder 17, as shown in FIG. 2, may be omitted from the press of FIG. 6 if the press is to be used only with web material having a width substantially equal to the length of the drawing rolls 1 and 21.

. in FIG. 4 is shown in enlarged detail a single cylindrical disclike weight element 23 for making up the upper roll 21. Each element 23 is provided with an elastic outer cover 24 around the circumference, constructed of rubber or other suitable elastic material. Opposite side surface 27 of the elastic outer covers 24 are ground off evenly with the opposite side surfaces 26 of the central hub portion of the discs 23. A number of discs 23 are assembled on the common shaft 22, which is relatively elastic in comparison to the lower roll 1 and the adjacent side surfaces 26 of the hub portions of the disc weight abutt lightly against one anOther so that the deflection or bending of the shaft 22 is not inhibited substantially. The light contact between side surfaces 27 of adjacent elastic outer covers 24 of the discs 23 likewise does not hinder the bending or deflection of the shaft 22. Outwardly of the hub portion 26 each disclike weight element 23 is formed with an annular recess 29 on both sides in order to reduce the amount of frictional contact or wear between adjacent disc elements 23 in an assembled upper rOll 21. Each disclike weight element 23 is provided with a central bore 28 so that the element may be slip fitted easily onto the shaft 22, with slight play for free rotation on the shaft without binding.

The lower roll 1 is relatively rigid in comparison to the upper roll 21 which is of relatively elastic construction. The plurality of separate, disclike, weight elements 23 are mounted on a common elastic shaft 22, and each element is urged by its own deadweight independently of the others toward the lower roll 1 without the necessity of any exterior downward pressure exerted on the roll through the support arms 16. The deadweight of the weight elements 23 of the upper roll 21 is chosen so that when a web 18 of width substantially the same as the length of the rolls is used, maximum tension can be transmitted to the web by the feed rolls.

Changing of the specific application pressure exerted by the rolls on the web relative to changes in web width is normally not necessary. The shaft 22 is of flexible construction so that it can adapt itself to any bending in the lower roll 1, but at the same time the shaft 22 is rigid enough to prevent shaft wobbling during rotation. It has been found expedient to choose the diameter of the shaft 22 in such manner that the angular impulse of the shaft is about 20 times less than that of lower roll 1. When the upper roll 21 is in contact with the web 18 moving over the lower roll 1 about one-twentieth, or percent, of the deadweight of the upper roll goes mainly onto the web edge portions and the remaining 95 percent of the weight is distributed uniformly over the entire width b of the web in application wherein the web width is approximately equal to the length of the rolls. When narrow webs in relation to the length of the rolls are processed, the web is passed through to the press at or near the middle or central portion of the rolls, and by means of the air cylinders 17, the arms 16 may be pivoted to exert upward lift on the upper roll 21. This lifting action is adjusted to compensate for the narrow web width by reducing the effective weight of the upper roll portions which overhang the web outwardly of the opposite side and which do not come in contact with the web. In this manner, the pressure exerted by the roll 21 on a narrow web may be maintained substantially the same as that for a wider web and is substantially uniform over the entire width of the web along the line of contact with the rolls.

The upper roll of the drawing press of FIG. 6 is offset laterally forwardly of the lower roll 1 in the same' manner as illustrated in FIG. 2, and the offset measured angularly as shown in about relative to the vertical. The upper roll 21 is offset in the same direction as the travel of the web through the rolls. The arrow K represents the pressure or force component exerted by the rolls 1 and 21 on the web 18. The relatively short arrow K perpendicular or normal to the arrow K represents the movement or force produced by the offset of the upper roll in the running direction of the web, and this force acts on the web with a spreading out effect which reduced any tendency of the web to crease or wrinkle, especially in the cases where a web consists of undulatory material.

The invention as shown and described provides an effective means of maintaining a desired specific roll application pressure on the web distributed uniformly across the entire width b. As shown in FIG. 5a, uniformity of roll pressure on the web material across the entire width of the web along the rolls reduces possible feeding errors, and this becomes especially important in applications when simultaneous feeding of a plurality of webs in a multilayer arrangement with one web on top of another is utilized. As FIG. 5 illustrates, not only is the upper roll 21, including each disclike weight element 23, provided with an elastic cover 25, but the lower roll 1 is similarly provided with an elastic cover 35. Because of the elastic covers, a planar flattening zone is produced in the web 18 between the rolls 1 and 21 by the application of pressure between the rolls and along the plane of the arrow K. This planar flattening zone is achieved by making the rolls 1 and 21 of equal diameter held constant throughout the length of the rolls. The respective elastic covers 25 and 35 are equal in outer diameter and thickness, and the elasticity of the material of both covers is equal. Preferably, the same material is used for both of the elastic covers 25 and 35, and when this is done a further advantage is achieved in that even with a natural aging of the material, which is generally accompanied with a loss of elasticity, a mutual flattening between the two roll covers remains equal in magnitude, and the plainness of the flattening zone, which is necessary for conveying the webs without feeding errors, is maintained.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In combination, an elongated web of substantial width comprising a plurality of layers of thin flexible sheet material superimposed on one another and a feed roll assembly for moving said web in tracking alignment without relative displacement between said layers, comprising a first lower driven roll having an elongated cylindrical body of relatively firm construction and supported at opposite ends for rotation about an axis transverse of said elongated web in driving engagement therewith, and a second upper roll above said first roll for biasing the layers of said web downwardly together with substantially uniform pressure across the width of said web against said first roll, said second roll comprising an elongated shaft of elastic material substantially parallel of and relatively small in diameter with respect to said first roll and a plurality of separate, cylindrical weight elements substantially narrower than said web mounted for free rotation on said elastic shaft independent of one another in closely adjacent side-by-side relation across the width of said web, each weight element acting substantially independently under its own deadweight to press said layers together with substantially uniform pressure across the web against said driven first roll.

2. The combination of claim 1 wherein the moment of inertia of said shaft is substantially smaller than that of said lower roll.

3. The combination of claim 2 wherein said moment of inertia of said shaft is smaller by a multiple than that of said lower roll.

4. The combination of claim 1 wherein the moment of inertia of said shaft is approximately twenty times less than that of said lower roll.

5. The combination of claim 1 including elastic covers mounted around the outer circumference of said weight elements for engagement with said web.

6. The combination of claim 5 including an elastic cover mounted around the circumference of said lower roll for engagement with said web.

7. The combination of claim 6 wherein the outer diameters of said weight elements and said lower roll are equal.

8. The combination of claim 6 wherein the thickness of said covers on said weight elements and lower roll are substantially equal and the material of said covers is the same.

9. The combination of claim 1 including means supporting opposite ends of said shaft for movement toward and away from said lower roll for supporting weight elements outboard of the edges of one of said webs having a width less than that of said lower roll.

10. The combination of claim 1 wherein said shaft is in parallel horizontally offset relation with said lower roll in the direction of travel of said web therebetween. 5

t i l l 

1. In combination, an elongated web of substantial width comprising a plurality of layers of thin flexible sheet material superimposed on one anotHer and a feed roll assembly for moving said web in tracking alignment without relative displacement between said layers, comprising a first lower driven roll having an elongated cylindrical body of relatively firm construction and supported at opposite ends for rotation about an axis transverse of said elongated web in driving engagement therewith, and a second upper roll above said first roll for biasing the layers of said web downwardly together with substantially uniform pressure across the width of said web against said first roll, said second roll comprising an elongated shaft of elastic material substantially parallel of and relatively small in diameter with respect to said first roll and a plurality of separate, cylindrical weight elements substantially narrower than said web mounted for free rotation on said elastic shaft independent of one another in closely adjacent side-by-side relation across the width of said web, each weight element acting substantially independently under its own deadweight to press said layers together with substantially uniform pressure across the web against said driven first roll.
 2. The combination of claim 1 wherein the moment of inertia of said shaft is substantially smaller than that of said lower roll.
 3. The combination of claim 2 wherein said moment of inertia of said shaft is smaller by a multiple than that of said lower roll.
 4. The combination of claim 1 wherein the moment of inertia of said shaft is approximately twenty times less than that of said lower roll.
 5. The combination of claim 1 including elastic covers mounted around the outer circumference of said weight elements for engagement with said web.
 6. The combination of claim 5 including an elastic cover mounted around the circumference of said lower roll for engagement with said web.
 7. The combination of claim 6 wherein the outer diameters of said weight elements and said lower roll are equal.
 8. The combination of claim 6 wherein the thickness of said covers on said weight elements and lower roll are substantially equal and the material of said covers is the same.
 9. The combination of claim 1 including means supporting opposite ends of said shaft for movement toward and away from said lower roll for supporting weight elements outboard of the edges of one of said webs having a width less than that of said lower roll.
 10. The combination of claim 1 wherein said shaft is in parallel horizontally offset relation with said lower roll in the direction of travel of said web therebetween. 